The invention relates to a tool coupler for a clamping system, in particular for clamping a welding saddle to a plastic pipe. The invention further relates to a clamping system, in particular for clamping a welding saddle to a plastic pipe having such a tool coupler, and to a tensioning ratchet for a clamping system, in particular for clamping a welding saddle to a plastic pipe, and to a method for clamping a welding saddle to a plastic pipe.
In order to provide additional branches, outlets or inlets in plastic pipelines that may already be laid, for example pipelines for carrying water, gas, oil, or the like, it is common practice to affix welding saddles by plastic welding to a peripheral surface of the plastic pipe. These welding saddles generally have a pipe connector in which, for example, a valve or the like is provided, and a curved flange collar which matches the outer curvature of the plastic pipe so that surface engagement can be produced between the flange collar and the plastic pipe. After the contact location on the plastic pipe has been cleaned, for example by peeling, the welding saddle is placed and fixed onto that location. To do that, the welding saddle has to be pressed with a specific pressing force against the outer pipe casing. An established technique in the prior art is to use tensioning ratchets and ratchet tie-down straps, such as those which are frequently used in the field of logistics as well, and which can be obtained, for example, from SpanSet Ltd., Cheshire, Great Britain. The ratchet lashing straps are generally arranged axially spaced apart from each other around the circumference of the plastic pipe and adjacent to the pipe connector of the welding saddle in such a way that the straps lie on an outwardly oriented surface of the flange collar of the welding saddle and thus press the welding saddle against the pipe. Compared to tensioning chains, the advantage of such ratchet lashing straps, which generally have textile straps, is that they do not damage the pipe. The straps are then tensioned manually by means of ratchet levers provided on the tensioning ratchet by the manufacturer. It has proved practicable in this regard to additionally use a tension force indicator (TFI), which can likewise be obtained from SpanSet Ltd. This element is disposed on the tensioning ratchet, at the point of connection between the strap and a frame of the tensioning ratchet, in such a way that a load is applied to it when the strap is tensioned. A scale then indicates the respective tensile force acting on the strap. The tensile force acting on the strap is an indicator for the contact pressure of the welding saddle against the pipe.
However, the disadvantage here is that the force indicator of the TFI does not always work reliably, due to the curvature of the pipe. When tightening the strap by means of the manually operated tensioning ratchet, the TFI may also slip and be difficult or even impossible to read. Another problem, particularly in the case of large plastic pipes, is that very strong clamping forces of 10 kN or more are needed, and that these are difficult to achieve with the clamping levers provided by the manufacturer on manually operated tensioning ratchets. At present, there are no TFIs available on the market that can indicate clamping forces of 10 kN or more.